organs. Among these tables, also, there is a series, prepared by Prof. W. O. Atwater, showing the percentages of nutrient ingredients in a large number of food-materials, the fuel-values in the same, and standards for dietaries for different classes and occupations. Another table shows the expectation of life as derived from records of life-insurance companies, and from the last United States census.
The Anatomy of the Frog. By Dr. Alexander Ecker. Translated, etc., by George Haslam, M. D. Illustrated. Oxford: Clarendon Press; New York: Macmillan & Co. Pp. 449, with Colored Plates. Price, $5.25.
The frog is aptly designated by the author as eminently the physiological domestic animal. It is kept in every physiological laboratory, and is daily sacrificed in numbers on the altar of science. The physiologist has recourse to it, not only to obtain answers to new questions, but for the sake of demonstrating easily and quickly the most important known facts of the science. It has furnished the means through which many most important discoveries in physiology have been made. It has "afforded almost the only material for the investigation of the excitability of nerves and its associated electromotive changes, and also no inconsiderable part of the remaining nerve and muscle physiology." Much of our knowledge of the functions of the spinal cord is derived from experiment upon it. Its muscles have served for the investigation of the phenomena and the conditions of contraction. But for the web of its foot and the gills and tail of its tadpole, "we should not perhaps for a long time have arrived at a satisfactory knowledge of the existence and the conditions of the capillary circulation. Acquaintance with the constituents of the blood directly concerned in nutrition; important facts in the physiology of the blood and lymph; and insight into the laws of the heart's action, have all been obtained by observations and experiments on the frog. To it, also, in histology, we owe much of our knowledge of the structure of nerve-fibers, their origin and termination, their relations within the ganglia, and the structure of muscular fiber; and for the study of reproduction and development the frog has, next to the chick, afforded the most important material." The importance of students being well acquainted with the anatomy and structure of an animal which plays so prominent a part in their researches is obvious; and it is this which Dr. Ecker, who is Professor of Human and Comparative Anatomy in the University of Freiberg, and Dr. Haslam, have furnished in the present book. The original work of Prof. Ecker was published in 1864. A second part, embodying, besides the author's work, fruits of the researches of Prof. Wiedersheim, appeared in 1881-'82. The translation was undertaken by Dr. Haslam at the suggestion of Prof. A. Gamgee, and was accepted by the delegates of the Clarendon Press as one of the series of Foreign Biological Memoirs published by them. But it soon became evident that a mere translation would be unsatisfactory, and that it would be desirable to recast and modify parts of the book, and to give descriptions of the minute structure of the several organs. The translator has included the results of recent researches, and has added facts derived from his own observations.
The Elements of Astronomy. With an Uranography. By Prof. Charles A. Young. Boston: Ginn & Co. Pp. 470. Price, $1.55.
Prof. Young has prepared this text-book for use in high schools and academies, using in it much of the material and many of the illustrations of his larger work, General Astronomy. The author has tried to avoid going to an extreme in cutting down and simplifying, while giving a clear treatment of every subject. From the number of pages in the book it may be inferred that he has provided abundant material for a highschool course in astronomy. He has paid special attention to making all statements correct as far as they go, though many of them, on account of the elementary character of the book, are necessarily incomplete. No mathematics higher than elementary algebra and geometry is introduced into the text. In an appendix of some seventy pages, methods of making certain calculations and the construction of astronomical instruments are described. The Uranography comprises a brief description of the constellations visible in the United States, with four maps, from which the principal stars may be iden-
